Buggy code:
public class EuclidianStyleBar extends JToolBar implements geogebra . common . euclidian . EuclidianStyleBar , ActionListener { private static final long serialVersionUID = 1L ; EuclidianController ec ; protected EuclidianViewInterface ev ; protected Application app ; private Construction cons ; private ColorPopupMenuButton btnColor ; private ColorPopupMenuButton btnBgColor ; private ColorPopupMenuButton btnTextColor ; private PopupMenuButton btnLineStyle ; private PopupMenuButton btnPointStyle ; private PopupMenuButton btnTextSize ; private PopupMenuButton btnMode ; PopupMenuButton btnTableTextJustify ; PopupMenuButton btnTableTextBracket ; private PopupMenuButton btnLabelStyle ; private PopupMenuButton btnPointCapture ; private MyToggleButton btnCopyVisualStyle ; private MyToggleButton btnPen ; private MyToggleButton btnShowGrid ; private MyToggleButton btnShowAxes ; MyToggleButton btnBold ; MyToggleButton btnItalic ; private MyToggleButton btnDelete ; private MyToggleButton btnLabel ; private MyToggleButton btnPenEraser ; MyToggleButton btnHideShowLabel ; private MyToggleButton btnTableTextLinesV ; private MyToggleButton btnTableTextLinesH ; private PopupMenuButton [ ] popupBtnList ; private MyToggleButton [ ] toggleBtnList ; private JButton btnPenDelete ; private JButton btnDeleteGeo ; private HashMap < Integer , Integer > defaultGeoMap ; private ArrayList < GeoElement > defaultGeos ; private GeoElement oldDefaultGeo ; protected int iconHeight = 18 ; private Dimension iconDimension = new Dimension ( 16 , iconHeight ) ; public int mode = - 1 ; private boolean isIniting ; private boolean needUndo = false ; private Integer oldDefaultMode ; private boolean modeChanged = true ; AlgoTableText tableText ; Integer [ ] lineStyleArray ; Integer [ ] pointStyleArray ; HashMap < Integer , Integer > lineStyleMap ; HashMap < Integer , Integer > pointStyleMap ; final String [ ] bracketArray = new String [ ] { "Ø" , "{<seq2seq4repair_space>}" , "(<seq2seq4repair_space>)" , "[<seq2seq4repair_space>]" , "|<seq2seq4repair_space>|" , "||<seq2seq4repair_space>||" } ; private final String [ ] bracketArray2 = new String [ ] { "Ø" , "{<seq2seq4repair_space>}" , "(<seq2seq4repair_space>)" , "[<seq2seq4repair_space>]" , "||" , "||||" } ; public EuclidianStyleBar ( EuclidianViewInterface ev ) { } public int getMode ( ) { } public void setMode ( int mode ) { } protected boolean isVisibleInThisView ( GeoElement geo ) { } public void restoreDefaultGeo ( ) { } public void updateStyleBar ( ) { } private void updateTableText ( Object [ ] geos ) { } private void createDefaultMap ( ) { } private void initGUI ( ) { } protected PopupMenuButton [ ] newPopupBtnList ( ) { } protected MyToggleButton [ ] newToggleBtnList ( ) { } protected void addBtnPointCapture ( ) { } protected void addBtnRotateView ( ) { } protected void createButtons ( ) { } private void createColorButton ( ) { } private void createBgColorButton ( ) { } static boolean checkGeoText ( Object [ ] geos ) { } private void createTextButtons ( ) { } private void createTableTextButtons ( ) { } protected void updateGUI ( ) { } public void actionPerformed ( ActionEvent e ) { } protected void processSource ( Object source , ArrayList < GeoElement > targetGeos ) { } public void updateButtonPointCapture ( int mode ) { } private void applyLineStyle ( ArrayList < GeoElement > geos ) { } private void applyPointStyle ( ArrayList < GeoElement > geos ) { } private void applyColor ( ArrayList < GeoElement > geos ) { } private void applyBgColor ( ArrayList < GeoElement > geos ) { Color color = geogebra . awt . Color . getAwtColor ( btnBgColor . getSelectedColor ( ) ) ; float alpha = ( btnBgColor . getSliderValue ( ) ) // 100.0F ; for ( int i = 0 ; i < ( geos . size ( ) ) ; i ++ ) { GeoElement geo = geos . get ( i ) ; if ( geo instanceof TextProperties ) if ( ( ( geogebra . awt . Color . getAwtColor ( geo . getBackgroundColor ( ) ) ) != color ) || ( ( geo . getAlphaValue ( ) ) != alpha ) ) { <START_BUG> geo . setBackgroundColor ( new geogebra . awt . Color ( color ) ) ; <END_BUG> geo . updateRepaint ( ) ; needUndo = true ; } } } private void applyTextColor ( ArrayList < GeoElement > geos ) { } private void applyFontStyle ( ArrayList < GeoElement > geos ) { } private void applyTextSize ( ArrayList < GeoElement > geos ) { } private void applyHideShowLabel ( ArrayList < GeoElement > geos ) { } private void applyCaptionStyle ( ArrayList < GeoElement > geos ) { } private void applyTableTextFormat ( ArrayList < GeoElement > geos ) { } public void applyVisualStyle ( ArrayList < GeoElement > geos ) { } public GeoElement redefineGeo ( GeoElement geo , String cmdtext ) { } public void setLabels ( ) { } }

Fix:
geo . setBackgroundColor ( ( color == null ? null : new geogebra . awt . Color ( color ) ) ) ;